My bad. I'm new here. This is more specific to what I was looking at in the second link, from another page:
On March 28, 1979 the body of Angela Desiree Kelly was discovered on the curb of the southbound lanes of the 7800 block of Red Bluff Rd. in Pasadena. The victim came to her death as a result of strangulation and was found with her hands bound behind her back. The death of Angela Desiree Kelly was ruled a homicide by the Harris County Medical Examiner’s Office. The victim was discovered by a motorist who phoned the police department.
I was just looking at missing or murdered in the area within a certain number of years. The hands bound and after club activity were really the only connections, but I think a case this old has been exhausted of a lot of the bigger details and it might be worth turning some smaller stones to see what comes up.
On a side-note, the Dallas area has a lot of similar stories, whether it's the work of only a couple people or quite a few.
I think it's interesting how the killer evolved though. The first incident was a rape. He covered his face and potentially lied about his description to throw her off, and so he clearly had no intent to kill. Mentioning the name Randy, like "where's Randy?" also has a certain implication to it, as in "where's your boyfriend when you need him?" That's how I read it anyway. Then you've got Andy, who is good looking and works in a gym. There could be a sort of bitterness toward men who can be with the types of women that the murderer couldn't get to this. That would also play along with the fact that Andy had his throat cut so deep, as if there was rage behind it and the fact that he possibly had to watch Cheryl get raped. This whole thing could be anti-a-certain-type-of-guy.
Onto the evolution though. In the case of Cheryl and Andy, it seems the intent was clearly to kill, so what changed? Maybe the first was what it was, but maybe he feared being caught or had some paranoia in the fact that he could be identified or maybe almost was. The thing at lovers lane is a little more evolved, a little more complex. Maybe rape just wasn't enough and he had something more to prove or was seeking a bigger thrill for himself.
A thought about evolution though. If this guy was in a sense, went from rapist to murderer, it seems as if it wouldn't have stopped there, unless:
1) He was close to being caught or paranoid about being caught and stopped or eased back
2) He was caught but never connected to this
3) He still did this, but somewhere else
4) He'd fulfilled whatever thrill he was looking for
5) He died
